Public aquariums house millions of fish in exhibit conditions that vary enormously in welfare quality. Understanding what good aquarium fish welfare looks like guides better standards and choices.
Aquarium fish welfare varies dramatically between institutions. Fish in well-managed aquariums with appropriate tank size, water quality, social grouping, and environmental complexity can show normal behavior including foraging, social interaction, and exploration. Fish in inadequate conditions show signs of chronic stress including abnormal swimming patterns, reduced color, and increased disease susceptibility. Wild capture for aquarium trade causes significant mortality at each supply chain stage, with cyanide fishing in some regions adding toxicity stress to capture trauma. The marine aquarium hobby and public aquariums both need stronger welfare standards that move beyond water chemistry to include behavioral welfare assessment.